A new mouse model of severe asthma

项目摘要 重度哮喘占所有哮喘病例的约10%，但占哮喘发病率的不成比例的高比例。 哮喘的卫生保健成本高，并导致患者生活质量的显著下降。临床上，这种形式 哮喘的定义是尽管使用大剂量吸入性皮质类固醇治疗， 与长效β2-激动剂（LABA）或白三烯调节剂联用。持续性气道阻塞， 增加的紧急护理利用和几乎致命的事件也是严重哮喘的特征。第二类-高 （T2-高）型重度哮喘是一种常见的重度哮喘亚型，其特征在于痰液 嗜酸性粒细胞增多、呼出的一氧化氮的升高分数和血清骨膜蛋白的增加。新的抗体- 基于T2高哮喘的治疗方法已经上线，这些治疗方法仅 部分有效且不足以缓解哮喘症状和生活质量指标。因此， 对于用于严重的2型高哮喘的新疗法的需求仍未得到满足。为了满足这一需求，我们试图 创建/鉴定一种新的重度高T2哮喘模型，可用于鉴定和测试新的治疗方法。 接近。我们从协作杂交小鼠遗传学参考群体中鉴定出一种品系，即 CC 011/UncJ（以下简称CC 011），出现极高水平的气道嗜酸性粒细胞增多症（总计） 和HDM特异性IgE，以及重复屋尘螨（HDM）过敏原后的气道高反应性 暴露量（25 µg/治疗，鼻内给药，每周3次，持续5周）。最令人印象深刻的是，CC 011小鼠 在治疗的第3-4周期间，HDM暴露后一致死亡，而 PBS处理的CC 011小鼠或任何其他30个测试的CC品系。重要的是，类固醇治疗并没有改善 嗜酸性粒细胞气道炎症。因此，CC 011代表了一种新的重度、T2高 哮喘为了进一步利用这种模型，需要研究这种表型的遗传学和免疫学基础， 被确定。在第一个目标中，我们将确定哪些细胞类型和途径与CC 011的整合有关。 对HDM的先天性和适应性免疫应答。我们将确定过敏性炎症是否依赖于T细胞 以及与BALB/cJ小鼠相比，CC 011小鼠中是否增强了CD 4 + Th 2细胞引发。我们将调查，如果 CC 011小鼠气道上皮细胞来源的alarmin（IL-25、IL-33、TSLP、IL-1α/β）增加， 这些细胞因子的中和可减轻变应性炎症。最后，我们要确定过敏原- 在CC 011小鼠中ILC 2的诱导扩增和活化增强。在第二个目标中，我们将确定 使用数量性状基因座作图方法，携带CC 011的易感等位基因的遗传基因座，和 然后利用CC 011和其他菌株的全基因组序列数据和基因表达数据， 鉴定候选基因。这些候选基因将成为未来研究的重点。总的来说，我们的 结果将建立CC 011 +HDM作为T2高重度哮喘的新模型，使其能够广泛用于 识别和测试新的治疗方法。

Project Summary Severe asthma comprises ~10% of all asthma cases but accounts for a disproportionately high degree of asthma health care costs and causes substantial decrements in quality of life for patients. Clinically, this form of asthma is defined by inadequate symptom control despite treatment with high-dose inhaled corticosteroids combined with a long-acting β2-agonist (LABA) or leukotriene modifier. Persistent airway obstruction, increased urgent care utilization, and near-fatal events are also features of severe asthma. The “Type 2-high” (T2-high) form of severe asthma is a common severe asthma sub-type that is characterized by sputum eosinophilia, elevated fraction of exhaled nitric oxide, and increased serum periostin. While new, antibody- based treatment approaches for T2-high asthma have come online, these treatment approaches are only partially effective and do not sufficiently alleviate asthma symptoms and quality of life metrics. Thus, there is still an unmet need for new therapeutics for severe Type 2-high asthma. To address this need, we sought to create/identify a new model of severe T2-high asthma that could be used to identify and test new therapeutic approaches. We identified a strain from the Collaborative Cross mouse genetics reference population, namely CC011/UncJ (hereafter referred to as CC011), that develops extremely high levels of airway eosinophilia, total and HDM-specific IgE, and airway hyper-responsiveness after repeated house dust mite (HDM) allergen exposure (25 µg/treatment by intranasal administration, 3x/week for 5 weeks). Most impressively, CC011 mice consistently died after HDM exposure during weeks 3-4 of treatment, whereas there were no deaths among PBS treated CC011 mice or any other 30 CC strains tested. Importantly, steroid treatment did not ameliorate eosinophilic airway inflammation in this strain. Thus, CC011 represents a new model of severe, T2-high asthma. To further the utility of this of this model, the genetic and immunologic basis of this phenotype need to be determined. In the first aim, we will identify which cell types and pathways are integrally involved in CC011’s innate and adaptive immune responses to HDM. We will determine if allergic inflammation is T cell-dependent and if CD4+ Th2 cell priming is augmented in CC011 mice compared to BALB/cJ mice. We will investigate if airway epithelial cell-derived alarmins (IL-25, IL-33, TSLP, IL-1α/β) are increased in CC011 mice and whether neutralization of these cytokines ameliorates allergic inflammation. Finally, we will determine if allergen- induced expansion and activation of ILC2s are enhanced in CC011 mice. In the second aim, we will identify the genetic loci that harbor CC011’s susceptibility alleles using a quantitative trait locus mapping approach, and then leverage whole genome sequence data and gene expression data from CC011 and other strains to identify candidate genes. These candidate genes will become the focus of future investigations. In total, our results will establish CC011+HDM as a new model of T2-high severe asthma, enabling its widespread use to identify and test new therapeutic approaches.